Env var for --skani_sketch_di

[tseemann]

Is it possible to specify --skani_sketch_dir globally via an env-var so it is default used on a shared unix system?

This would be particularly useful given r232 may come with the sketches?

[pchaumeil]

Hello Torsten,

The skani sketch database will replace the individual genomes in the GTDB-Tk database package, so the sketches will be distributed as part of the standard Tk database.
Users should continue using GTDBTK_DATA_PATH and --skani_sketch_dir flag will be discarded.